_RP_550-1-1-1986_scan.pdf

Manual on Installation of RefineryInstruments and Control SystemsiPartl-Process Instrumentation and Con入Section 1-FlowRECOMMENDED PRACTICE 550ENTRO OE INFORMAGFOURTH EDITION,MARCH 1986American Petroleum Institute1220 L Street,NorthwestWashington,D.C.20005API RP 550-PART I卡wHd.THISSTAMPED ON UPSTREAMLINESIDE OF THE PLATESIZEINLET”6 mm)DIA HOLEPLATE BEFOREORIFICE HOLEIS MADESHARPSQUARE EDGESd0000530045DRECTIONOF FLOWCHAMFER ORDOWNSTREAMWHEN tTOPTIONA3nHOLNSECTIONZONTAL LINESS O0POF LINEOR L IQUIDCONTAININGVAPOR ORNONCONDENSABL ESOrifice Plate Outside Diameters to Fit ANSI Service Rated Flange UnionsCLASSNominalTABPipe Size人30060090015002500Lw3名43%4%5%55%53/4a3%43地5%6%67/e7%47%75%8%8%49%a6A6%9%10211%11/%12h61。12%12%14%13%154144153%17%17%18%612165/%1819%20h215%6119%19%20h22%61621422%225%254623h24%25%27/%60州%25%267%27229%42%30h31%3335hNOTES:1.All measurements in inchescommercially:any plale departing from flatness along any diameter more2.The outside diameter(OD)of the orifice plate is that required to fit in-than 0.010 perinch(.25 millimeters)of dam height.(D-d)/2.shall be unacside the bolts of standard ANSI flanges.The outside diameter is equal toceptable.Surface roughness shall not exceed 50 microinches in a band atthe diameter of bolt circle minus thenominal diameter of bolt.within aleast 0.25 diameter wide around the oritice bore.manufacturing tolerance of+0 inches,-%2 inch(+0 millimeters,-.85.All seating surfaces for spiral-wound gaskets should be clean and freeof rust,burrs.nicks,and so forth.Any surface not meeting the following3.For orifice plate outside diameters in flange sizes and ratings not listedolerances should be relapped:above,refer to gasket OD dimensions given under Figure 3.Table 1,Ap.(a)Roughness:Should not exceed 80 root mean square with 63 root meanpendix Ein ANSIB16.591.Sreel Pipe Flanges and Flanged Fiisquare or better as optimum.vailable from the American Society of Mechanicl Engineers.345 East(b)Flatness:Out-of-plane tolerancesmust not exceed 0.0025 inch(0.0647th Street.New York,New York 10017.millimeter).The cumulative out-of-flatness for two mating surfaces shall4.The upstream face of the orifice plate shall be as flat as can beobtainednot exceed 0.0040 inch(0.I millimeter).Figure 1-1-Concentric Orifice Plate